Being Alive - What is its Meaning? — BIOLOGY STD 9 — Question

Irritability is a feature shown by living beings, but not non-living things. It refers to the ability of the organism to respond in accordance with internal or external environmental stimuli. Irritability is well-developed in animals due to the evolution of the nervous system. An example is the immediate removal of a hand from a hot object. Irritability is also shown by plants but it is not very prominent.